There are storage limits or resource limits in the game which limit the number of resources to be stored.
For 1 base: 50.000.000 per resource
From 5 bases: 75.000.000 per resource
From 20 bases: 150.000.000 per resource
When you have reached the stock limit for a resource, you can no longer produce that resource as long as the stock is full. The limit depends on how many base stations you have in total.
Since there is only one resource warehouse for all cards, this is your total limit.
When the limit is reached, all factories stop and open productions are credited. So the platinium is not lost.